Why are some supernovas much more powerful than others? Astronomers are still trying to figure that out, but one new discovery may help answer the question. On November 3, 2010, a supernova was discovered in a galaxy located about 160 million light years from Earth. When astronomers used the Chandra X-ray Observatory to look at it, they found some very interesting clues. The Chandra data showed evidence that the shock wave formed by the supernova was, in fact, breaking through a cocoon of gas. This cocoon was probably formed when the star expelled its outer layers before finally collapsing on itself and exploding as a supernova. By observing this supernova just weeks after the initial explosion, scientists were able to learn more about this supernova and potentially others as they try to better understand how some stars die.
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In movies, heroes and villains are thrown forward after an explosion. This is because a powerful wave of energy, called a shock wave, is released. In space, the same thing happens when a star explodes in what is called a supernova explosion.

The shock wave from the supernova is absorbed by the star's outer shells of gas and dust, which escaped from the star before the explosion. It heats the gas so that it gives off X-ray radiation, which astronomers can photograph using special telescopes in space.

Astronomers took two pictures of this glowing cloud of gas and dust, which were taken about a year apart. By comparing the two X-ray photos, astronomers think that the shock wave is finally escaping from the cloud. This is the first time that astronomers have X-ray evidence for a shock wave breaking free from its gassy and dusty cocoon!
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